CD80 and infection: However, virus replication in CD80-/- mice after infection with HSV-CD80 virus was similar to that in the WT-infected group, suggesting that the absence of CD80 in CD80-/- mice was compensated by expression of CD80 by HSV-CD80 virus, which increased viral titers in the infected eyes of CD80-/- mice, but not in those of the WT-infected mice.